While initiating and maintaining gonorrheal infection, gonococci encounter and must interact with a multitude of cellular and soluble macromolecules of their human host; these include such diverse constituents as epithelial cells, neutrophils, DNA and other debris of damaged host cells, mucins of urethral secretions, urine contents, and semen. Such interactions with host components likely depend partly on the physicochemical properties of gonococci, including surface charge. The overall aim of this project is to understand which surface components contribute to the electrostatic charge of gonococci and whether charge has any relevance to biological interactions of these organisms with host components. Earlier studies established that polyanions such as heparin, dextran sulfate, and DNA accrete to gonococci expressing certain Opa proteins, thereby endow gonococci with marked negative charge and markedly altering the bacterium~s behavior. In addition to extending those studies, recent work has explored the interactions of gonococci with selected polycationic molecules such as protamine which occurs in semen.